Refreshing Air Arrives In Vermont, But Frustrating Flood Potential Forecast For End Of Week

Forecast rainfall for the next seven days. Anything orange
is three inches or more. Darker shades near NYC indicate
at least five inches. Yellow in the Carolinas is over
ten inches. This forecast is big time subject to
change, especially in the Northeast. 

 As expected, it's much cooler and drier out there this morning, a state of affairs that will last most of the week.  

Clouds are forecast to gradually clear today after yesterday's rain. That rain was torrential in spots, nearly non-existent in others. 

Burlington received just 0.02 inches of rain. Meanwhile, a stripe of Addison County was under a flood warning for a time last evening as a patch of torrents passed through.

 Luckily, I've so far seen no reports of any serious damage in that neck of the woods. 

Now that we're done with the storms and oppressive weather,  there is pretty much no sign of any return to high temperatures combined with high humidity for the foreseeable future, so all good, right?

Unfortunately, no. Or at least maybe not. As I've mentioned a couple times already in previous posts, there's big time flood potential later in the week up and down the Eastern Seaboard. 

We don't know yet whether that includes flood-weary Vermont. 

DEBBY DANGER

Tropical Storm Debby so far is pretty much following forecasts, meandering around the Southeast, dumping incredible amounts of rain that is and will cause historic flooding in swaths of Georgia and the Carolinas. 

It's about to limp its way from Georgia and park itself just offshore. Since the center will be a little off the coast, Debby will have a chance to re-strengthen for awhile. All that time, it will be slamming huge amounts of rain into Georgia and South Carolina. 

It'll take until about late Friday or Saturday for Debby or its remnants to become "unstuck" and head on off to the northeast at a decent pace. 

During this time, we'll have that cool high pressure near us, keeping us partly to mostly sunny through Thursday, though clouds might be thicker south. 

Meanwhile another storm will be coming in from the west. We know the combination of that system from the west and Debby will cause a dangerous flood situation up and down the East Coast.  What we don't know is exactly where that will happen. The question marks are biggest in New England. 

This is a situation for a classic set up know as a Predecessor Rain Event or PRE.  Often, ahead of a tropical system, an area of torrential rain will develop well to the north and west of the tropical storm. It often but not always forms in an area that will eventually get hit by the actual tropical storm or hurricane.

A PRE can develop as much as 600 miles north or west of a tropical storm, and they're really hard to forecast. That's why meteorologists are still hemming and hawing about where flooding rains will strike at the end of the week. 

VERMONT QUESTIONS

As the National Weather Service in South Burlington points out in its forecast discussion this morning, computer  models are still all over the place when it comes to where the heavy rain sets up in New England toward Friday and Saturday.

The models are sort of leaning toward the heaviest rain focusing on southern Vermont, but there is absolutely no unanimity among the computer models, and various runs of those models. 

 Some of them have a  best case scenario (for us, anyway) of having almost no rain over central and northern Vermont and bringing the bad stuff to southern New England.  

Other models have a worst case scenario of dumping inches of torrential rains smack dab over the middle of the Green Mountain State.  

Other computer models have something in between those two extremes.   

Obviously, we want to avoid the worse case scenario, especially after the kind of summer we've had so far. Some Vermont communities have had serious flooding five times in the past year.  We've had more than our fill. 

To get forecast clarity, we'll have to wait until we see how Debby's path evolves, and how Debby and its moisture interact with that storm system coming in from the west. 

Hopefully, we'll start to get a clear picture by Thursday, so that we have a little time to prepare for flooding, if that's the direction we're headed. We just don't know.